Examining the supermassive black hole in our galaxy

The supermassive black hole (SMBH) at our galaxy's core, Sagittarius A*, is modest in size with only 4.15 million solar-masses. The Event Horizon Telescope (EHT) recently released a dramatic submillimeter image of it as seen ...

Scientists identify a possible source for Charon's red cap

Southwest Research Institute scientists combined data from NASA's New Horizons mission with novel laboratory experiments and exospheric modeling to reveal the likely composition of the red cap on Pluto's moon Charon and how ...

Scientists discover rapidly growing black hole

The fastest-growing black hole of the last 9 billion years has been discovered by an international team led by astronomers at The Australian National University (ANU).

Research confirms effectiveness of oil dispersants

Marine oil spills are one of the most direct, and harmful, examples of the toll that the extraction of fossil fuels can take on the environment. One of the few tools to mitigate that damage are chemical dispersants that break ...

Milky Way's black hole was 'birth cry' of radio astronomy

The first image of the supermassive black hole at the center of our Milky Way galaxy brings radio astronomy back to its celestial birthplace. The Event Horizon Telescope (EHT), a worldwide collection of millimeter-wave radio ...

Snapping a black hole: How the EHT super-telescope works

Powerful enough to spot a golf ball on the moon, the Event Horizon Telescope (EHT) is a network of radio dishes designed to detect the light cast when matter disappears into the maw of a black hole.

A space telescope could reveal a black hole's photon ring

Despite decades of study, black holes are still among the most powerful and mysterious celestial objects ever studied. Because of the extreme gravitational forces involved, nothing can escape the surface of a black hole (including ...

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The horizon (or skyline) is the apparent line that separates earth from sky, the line that divides all visible directions into two categories: those that intersect the Earth's surface, and those that do not. At many locations, the true horizon is obscured by trees, buildings, mountains, etc., and the resulting intersection of earth and sky is called the visible horizon. When looking at a sea from a shore, the part of the sea closest to the horizon is called the offing. The word horizon derives from the Greek "ὁρίζων κύκλος" (horizōn kyklos), "separating circle", from the verb "ὁρίζω" (horizō), "to divide, to separate", and that from "ὅρος" (oros), "boundary, landmark".

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